Great GoogaMooga, a brand-new food-and-music extravaganza, invades Prospect Park’s Nethermead Meadow today and tomorrow. The Roots and Hall & Oates are among the headlining performers, but it’s the chow that’s getting all the attention. Free general admission tickets are all snatched up, though $249.50 passes to “Extra Mooga” — a mini festival within GoogaMooga — can still be your golden ticket for entry.